Field of the Invention
The present invention relates to ferroelectric ceramics and a method for manufacturing thereof.
Conventional method for manufacturing Pb(Zr, Ti)O3 (hereinafter referred to as “PZT”) film will be explained. This PZT film is one example of a perovskite-type ferroelectric ceramics.
A SiO2 film having a thickness of 300 nm is formed on a wafer of Si of 4 inches, and a TiOx film having a thickness of 5 nm is formed on the SiO2 film. Next, a Pt film having a thickness of 150 nm oriented, for example, in (111) is formed on the TiOx film, and a PZT sol-gel solution is coated on the Pt film under rotation by a spin coater. The spin condition at this time is a condition of rotation at 1500 rpm for 30 seconds, and then at 4000 rpm for 10 seconds.
Next, the thus coated PZT sol-gel solution is dried by keeping with heating on a hot-plate at 250° C. for 30 seconds to remove water, and further, is pre-calcined by being kept under heating on a hot-plate at a high temperature of 500° C. for 60 seconds. A PZT amorphous film having a thickness of 150 nm is produced by repeating the procedure several times.
Subsequently, annealing treatment at 700° C. is performed on the PZT amorphous film by using a pressurized lamp annealing apparatus (RTA: rapid thermal anneal) to thereby carry out crystallization of PZT. The thus crystallized PZT film has the perovskite structure (refer to, for example, Patent Document 1).
Description of a Related Art
Patent Document
    [Patent Document 1] WO2006/087777    [Non-Patent Document 1] Rigaku Journal 39(2)2008, PP10-17 “Technical Note X-Ray measuring method of thin film Basic structure The third high resolution X ray diffraction method Takayuki KONYA”    [Non-Patent Document 2] Hunsai No. 56(2013), pp 38-41 “Special/Front line of application of nano particle technology Role and future advance of nano particles in ferroelectric piezoelectric device Yuji NOGUCHI, Yuki KITANAKA, Masaru MIYAMA”